植物残体输入改变对樟子松人工林土壤呼吸及其温度敏感性的影响

对河北塞罕坝机械林场樟子松(Pinus sylvestris var.mongolica)人工林采取不同的处理方式(对照(CK)、凋落物移除(-L)、凋落物添加(+L)、根系去除(-R)、凋落物和根系同时去除(-R-L)、凋落物添加和根系去除(-R+L)),基于处理后第一个生长季(2019年5—9月)的测定结果,研究不...

Effects of Altered Plant Detritus Input on Soil Respiration and Its Temperature Sensitivity in a Pinus sylvestris var. mongolica Plantation

Six treatments (control (CK), litter removal (?L), litter addition (+L), root removal (?R), litter and root removal (?R?L), litter addition and root removal (?R+L)) were conducted in a Pinus sylvestris var. mongolicaplantation in Saihanba, Hebei Province. Based on the results of the first growing season (May–September 2019) after the treatments, we aimed to evaluate the effects of different plant detritus input on soil respiration and its temperature sensitivity. The results show that: 1) soil respiration rate exhibited significant seasonal dynamics, with peak value in July–August and minimum value in late September. The average soil respiration rates of control, litter removal, litter addition, root removal, litter and root removal, litter addition and root removal treatments were (mean±SE) 2.20±0.17, 1.24±0.09, 2.40±0.07, 2.05±0.11, 1.04±0.07 and 2.28±0.17 μmol/(m²·s) respectively. Compared to the CK, ?L and ?R?L significantly reduced soil respiration rate by 43.6% and 52.7%, respectively; 2) soil respiration in the growing season was significantly and exponentially correlated with soil temperature (p<0.01) among different treatments. The temperature sensitivity of soil respiration (Q₁₀ values) were 2.32±0.13, 2.37±0.05, 2.41±0.09, 2.42±0.14, 2.09±0.08 and 2.87±0.11, respectively. Aboveground litter treatment had significant effects on both average rate and Q₁₀ value of soil respiration (p<0.05), while belowground root treatment did not (p>0.05); 3) compared to CK, soil moisture was significantly higher in all root removal treatments (?R, ?R?L, ?R+L) likely due to the lack of water uptake by roots, but soil temperature did not change significantly. In most treatments (except ?R and ?R+L), soil respiration and soil moisture showed a significant parabolic relationship during the growing season, and the threshold of soil moisture was about 15% (v/v). In conclusion, the results showed that litter removal had significant effects on growing season soil respiration and its temperature sensitivity in the Pinussylvestris var. mongolica plantation, but root removal had no significant effect in the first growing season after the manipulation.